Machines used to cut hard surfaces such as concrete and asphalt paving and so forth employ rotatable tools mounted around the circumference of a drum with each of the tools having a tapered forward cutting end behind which is an axially extending shank that is rotatably fitted into a tool holder on the drum. Since the tools of the machine cut very hard materials, the tools must rotate to wear evenly around their circumference and thereby maximize their useful life. Nonetheless, the tools wear rapidly and where the machine is in constant use it is common to replace tools at least daily.
Over time, the tool holders that retain the rotatable tools to the drum must also be changed. The replacement of the tool holders on the surface of a rotatable drum can consume a great deal of time. It has therefore become common for the tool holders to include a base block mounting built on to the surface of the drum with the base block mounting having an axial bore into which a removable quick-change tool holder is fitted. It is the quick-change tool holder that actually holds the tool. The removable quick-change tool holder has an enlarged tapered forward end and a generally planar transverse forward surface at the forward end. Extending axially rearwardly of the enlarged forward end is a shank that is received in the complementarily shaped axial bore of the base block mounting on the machine. Ideally, the quick-change tool holders are easily removed from the base block mountings however, the strong forces applied by the base block mounting and the tool holder to the tools as the machine cuts hard surfaces cause the various parts to become deformed over time. The shank of a quick-change tool holder often becomes tightly lodged within the bore of the base block mounting such that its extraction is difficult.
Presently, it is the practice to apply one end of an elongate punch against the rear end of the shank of a worn tool holder and pound the punch with a hammer to drive the shank of the worn tool holder out of the base block mounting. This process, however, requires that the operator use both hands to extract the tool holder. Frequently, the rotatable drum is positioned at an orientation where it is difficult for the operator to reach both hands behind the base block mounting to position the punch and hammer to remove the worn tool holder and therefore an operator must frequently reposition the orientation of the drum in order to remove the worn tool holders. Also, because of the structure of the machines some tool holders are almost inaccessible to an operator and are very difficult to remove using a hammer and punch.
The process of removing worn tool holders can consume a great amount of time, and the down time for the machine adds to the cost of operating the machine. It would therefore be desirable to provide a simplified method of removing a worn quick-change tool holder from a base block mounting.